Inertia valve



July 26, 1960 M. K. FAlRcHl-LD ETAL INERTIA VALVE Filed Feb. 27, 1956nstnafrm VALVE Merl K. Fairchild, Torrance, Charles W. Maxelt, Los

Angeles, and Bernard P. Brady, Torrance, Calif., asesignors to NorthropCorporation, a corporation of California Filed Feb. 27, 1956, Ser. No.567,735

3 Claims. (Cl. 137-38) This invention relates to valves and moreparticularly to an inertia type valve having-special utility inpreventing fuel surge in compartmented tanks and the like during periodsof excessive acceleration.

It is well known that fuel contained in aircraft fuel Ycells .shiftsrapidly and quite frequently violently at such 'time as the aircraft inwhich the cells are mounted accelerates, decelerates or suddenly changesits flight course. In many instances such a shifting of the liquid fuelsubjects the cell and structural members of the aircraft to stressexceeding that which they are designed to withstand. Further, theshifting of the liquid fuel results in .a shifting of the center ofgravity of the fuel cell and accordingly of the aircraft itself. Thiscenter of gravity -shift may adversely affect the attitude of anaircraft during a critical phase .of its operation. For example, it isex- :tremely important that the center of gravity of a pilotless missilebe maintained at a xed position within the missile Yduring the launchingphase of the missile. Therefore it is important that the -missiles fuelsupply is not permitted to shift during a launching operation.

Accordingly it is an object of this invention to provide a uid valvewhich is responsive to inertial forces and which, when mounted betweencommunicating fuel cells or the like, functions to prevent fuel surgetherebetween at such time as the cells are subject to excessiveacceleration.

Another object is to provide a fluid valve functioning to control thesurge of liquid fuel or the like between communicating cells or adjacentcompartments of a unitary fuel cell at such times as the cells aresubjected to excessive acceleration and which voperates independently offuel surge which may occur within the subject cells.

Another object is to provide a fluid valve functioning to control thesurge of liquid fuel between communicating cells or adjacentcommunicating compartments of a unitary fuel cell at such times as thecells are subjected Vto excessive acceleration and which operatesequally Well although unequal iiuid heads are present in Vthecommunicating cells or adjacent compartments.

Another object is to provide a uid valve for effectively controlling thesurge of liquidfuel between communicating cells or adjacentcommunicating compartments of a unitary fuel cell which is simple indesign yet rugged in construction, which is economical to manufacture,and which because of fewoperating-parts is quite unlikely tomalfunction.

Although the Ycharacteristic features of the `present invention areparticularly pointed out in the appended claims, the invention itself,also the manner in which it may be carried out, will be betterunderstood by referring to the following description taken in connectionwith the accompanying drawings forming a part of this application and inwhich:

Figure 1 is a side elevational view of a pilotless missile positioned ina launching attitude and utilizing valves of the type disclosed hereinto control fuel surge between 2 the various compartments of a fuel cellmounted in the missile.

Figure 2 is a cross-sectional view 'taken along the line 2 2 of Figurel.

Figure 3 is a longitudinal crosssectional view of the valve shown inFigure 2.

Figure 4 is a view similar to Figure 3 'but showing `a differentembodiment of the valve as disclosed herein.

Figure 5 is a view similar to Figure 3 'butshowing the manner ofmounting duplicate valves to control fuel surge in both directionsnormal to a partition wall.

Referring to the drawings for a detailed description of a specicembodiment of the surge preventing valve as disclosed herein, Figure 1shows a pilotless missile 11 positioned in a launching attitude. Alsoshown in this figure is a fuel cell 12-l'ocated in the forward vportionof the fuselage of the missile 11. The cell 12 is of elongatedconguration in a fore and aft direction `and ,is divided into aplurality of compartments 14, 16, and 17 by longitudinally spacedpartition `walls 1S and 19. VMounted on the forward side of each of thewalls 18 and 19 is a surge preventing valve 21.

A missile of the type shown in Figure lis normally launched by means ofJATO type rockets (not'shown) which materially augment vthe thrust ofthe missiles .engine and subject the missile to violent acceleration.During the launching period it is extremely `important that the centerof gravity of the combined mass of the .loaded missile, JATO rockets,and various mechanical devices for attachment and ejection of therockets,'remain as nearly fixed as possible. 'For the above Vreason itis important that the fuel is not allowed to surge or shift during thelaunching period as this would Ibe a .contributing factor in Vcausingthe CG. of the missile `to shift. Also a surge or shift of fuel Withinthe cell l2 is highly undesirable as it subjects the cell'wallsandcertain structural members of the missile to excessive stress.

Referring to Figures 2 and 3 one `embodiment of the surge preventingvalve 21 is shown on an enlarged scale. The wall 18 shown in phantomconstruction is ported at 22. The port 22 is of circular configurationand is located a small distance above the lower portion of the wall 18to permit fuel flow between adjacent compartments `at practically alllevels of fuel'inthe fuel cell.

The valve 21 consists of a `cylindrical housing 23 Athe outer end ofwhich is closed by .an end wall 24. An integrally formed flange 26,located at Athe inner end of the housing 23, provides means forattaching the 'latter to the wall 18,as-by rivets 27 or the like. In theassembled pcsition of the housing 23 onthe wall 18 the housing isconcentrically located with respect Ato the port 22, the .port 22 beingslightly less in diameter than :the inside diameter of the housing 23.`A plurality of circumferentially spaced openings 28 are provided in.the cylindrical wall of the housing 23 adjacent .the flange 26.

Mounted in sliding relationship within `the housing 23 is a cylindricalsleeve element .29 which is open at .fboth ends and is of slightly ylesslength than Vthe distance libe- .tween the outermost portionsoftheopeningslZ'S and the wall 24. As mounted the sleeve element ismovable be'- tween a first or open'position Vand a:second.or-closed position. The rstpositionis characterizedin that the outer .end :of .thesleeve yelement 29 is :bottomed on the wall 24 and the inner end isclear of the openings 28. The second position is characterized in thatthe inner end of the sleeve element is bottomed on the portions of thepartition wall 18 extending inwardly of the housing 23 and thecylindrical walls completely close the openings 2S. The openings 28terminate a sun'icient distance from the flange 26 to substantiallypreclude liquid leakage between the housing 23 and sleeve element 29 atsuch time as the latter is located in its second or closed position.

Patented AJuly 26,v 1960 The inner cylindrical surface of the housing 23and the outer cylindrical surface of the sleeve element Z9 are lapped orsimilarly finished to provide mating surfaces which are easily slideablewith respect to each other and alsoto a high degree'preclude leakage'ofli'quid therebetween. In this respect it has been foundV that a 'steelsleeve positioned within Yan aluminumrhousing Vis most satisfactoryalthough it will be understood that other types of material may beequally satisfactory.

Assuming now that Ythe valve 21 is utilized in the missile 11 rof Figure1 and that the sleeve element is in its open position. `It will beapparent that upon a predetermined acceleration of the missile inertiaforces will act on the sleeve element causing it to slideably move toits closed position and remain in this position. Inasmuch as it is notdesirable to have the sleeve element 2.9 responsive to slight changes inacceleration of the missile a helical wound spring 31 is utilized tonormally maintain the sleeve element in its open position. The spring 31extends between a lug 32, extending inwardly from the wall 24 and a rod33, the latter extending diametrically across the sleeve element 29 atthe inner end thereof.

The spring 31, having a predetermined spring force, is selected to allowthe sleeve element to move to its closed position at such time as theacceleration of the missile equals a predetermined amount. For example,the spring 31 may be selected to allow the sleeve element to move to itsclosed position at such time as the acceleration fof the missile causesa 1A G force to be exerted on the sleeve element 29.

It will now be apparent that a valve is provided which will arrest liuidsurge between the compartments 14, 16, and 17 at such time as themissile is accelerated a predetermined amount. This valve is notaffected by fluid surge or iluid pressure but is entirely responsive toinertia forces. Further it will be apparent that the valve 21 willreopen, at such time as the speed of the missile becomes fairlyconstant, although there may be a difference in liquid heads on oppositesides of the partition wall 18. This latter feature, for example, wouldnot necessarily be true in the case of a llapper type valve. For such avalve a difference in liquid head may result in the valve failing toreopen for reasons which are well known in the art.

The valve 21 shown in Figure 4 is similar to the embodiment shown inFigure 3 and just described. In the embodiment shown in Figure 4,however, the sleeve element 29 is mounted on and mates with the outercylindrical wall surface of the housing 23. Also in the latterembodiment the spring 31' is mounted externally of the housing 23 andconstitutes a helical wound spring which functions under compressionrather than tension as is the case of the spring 31 of Figure 3.

The spring 31' is mounted by means of a yoke member A 34 the endportions of which are attached at diametrically opposite positions tothe sleeve element 29 as by welding or the like. A rod member 36,extending from the wall Z4 and supported at its outer end by a bearing37 provided by the yoke member 34, provides proper support for thespring 31'. The operation of the valve shown in Figure 4 and justdescribed is substantially the same as the operation of the valve shownin Figure 3 and, therefore, a further discussion in this connection isdeemed unnecessary.

The valves as described so far are positioned to arrest fluid surgeduring periods of acceleration of the missile 11 in a forward direction.However, it should be ap- :4,946,339 .Uf f' f parent that the valves 21or 21' may be positioned on either side of the partition walls of thecell 12 to arrest iluid surge either during periods of acceleration orydeceleration of the missile 11. Also it will be apparent that a pair ofvalves 21 or 21 may be util-ized on either side of the partition wall18, substantially as shown in Figure 5, for arresting fuel surge in rstone direction and than the other.

While in order to comply with the statute, the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprises the preferred form of putting the invention into effect, andthe invention is therefore claimed in any of its forms or modicationswithin the legitimate and valid scope of the appended claims.

What is claimed is: Y

l. In an aircraft the combination comprising: a fuel cell mounted insaid aircraft and including a ported partition dividing said cell intofore and aft compartments; a valve assembly including fore and aftunitary valves; said unitary valves include respective fore and aftcylindrical members each having a closed end, an open end, and aplurality of ports formed in the side walls thereof at positionsadjacent said open ends; said fore and aft cylindrical members beingmounted in said fore and aft compartments, respectively, with their openends surrounding the port in said partition and secured to the latter inabutting relation; fore and aft sleeve members integrated respectivelywith said fore and aft cylindrical members for slideable movementbetween respective open and closed positions allowing and arrestingfluid flow between said compartments; resilient means adapted tomaintain said sleeve members in their respective open positions at suchtimes as said aircraft does not exceed a predetermined accelerationeither in a fore or aft direction; and said sleeve members areresponsive to inertial forces in that one of said sleeve members movesto its respective closed position whiletlle other of said sleevermembersis in its open position and the other of said sleeve members moves toits respective closed posi- `tion while said one sleeve member is in itsopen position at such times as said aircraft exceeds said predeterminedacceleration in fore and aft directions, respectively.

2. Apparatus as set forth in claim' l: further characterized in thatsaid fore and aft -sleeve members are mounted internally of said foreand aft cylindrical members with the outer cylindrical wall surfaces ofsaid sleeve members in complete contact with the inner cylindrical wallsurfaces of the cylindrical member in which they are respectivelymounted.

3. Apparatus as set forth in claim l: further characterized in that saidfore and aft sleeve members are mounted externally of said fore and aftcylindrical members with the inner cylindrical wall surfaces of saidsleeve members in contact with the outer cylindrical Wall surfaces ofthe cylindrical members on which they are respectively mounted.

References Cited in the le of this patent UNITED STATES PATENTS2,377,350 Marsh June 5, 1945 2,485,514 Sturrock Oct. 18, 1949 2,678,660Gurin May 18, 1954 `2,733,726 Kaufman Feb. 7, 1956 uwu...

